Unfortunately, I don't have pictures to go along 
with all of these, (although I did manage to 
recover the zip disk with all of my scans!) but, 
I've got a couple so far that I've seen appear in 
things:
My cel of Lina and Sylphiel from Next ep. 25 
looks to be a dead-on match for the shot that's 
shown in the Slayers anime-film book for that 
episode arc.  My Martina cel from the same scene 
is very close, although I think there are a 
couple little differences..
Oddly enough, I almost didn't buy the above two 
cels when I first saw them, because I didn't 
remember the scenes (it'd been a while, although 
I really have no excuse for forgetting memorable 
scenes from one of my favourite Slayers eps.) 
until I was leafing through that film book, and 
realized just what they were.  
I also saw a Jubei-chan trading card on eBay 
(Which I should have bought!  I don't know why I 
didn't! >.<) that has a picture perfectly 
matching my Dark Shiro close-up.  
(Hm..I think I'll actually attempt an image...see 
if it works..)